CN204332835U - A Relay Driving Circuit with Anti-interference Capability - Google Patents

Abstract

A kind of relay drive circuit with antijamming capability.It comprises two resistor R1-R2, diode D1, two triodes Q1, Q2 and relay U1; The relay drive circuit that the utility model provides has following technique effect: 1, the utility model device used is less, and has higher antijamming capability, improves the reliability of whole system.2, peripheral components of the present utility model is made up of resistance, diode and triode, and complexity is lower, improves the machinability of product.3, drive circuit of the present utility model effectively can suppress the inverse overvoltage in short-term of relay shutdown moment.

Description

A Relay Driving Circuit with Anti-interference Capability

technical field

The utility model belongs to the technical field of electrical equipment drive, in particular to a relay drive circuit with anti-interference ability.

Background technique

In the power distribution system, a large number of load devices need to be driven by relays, and such loads often have strong EMI (electromagnetic interference) characteristics. Since electromagnetic interference can transmit energy through radiation and conduction, once the transmitted energy causes the level reversal of the control pin, it is easy to cause the relay to malfunction.

To sum up, it is necessary to improve the anti-interference ability of the relay drive circuit. At present, the vast majority of relay drive circuits can only meet the basic drive functions, but cannot guarantee the reliable operation of the circuit in a strong interference environment, and cannot perfectly solve the above problems.

Contents of the invention

In order to solve the above problems, the purpose of the utility model is to provide a relay drive circuit with anti-interference ability.

In order to achieve the above object, the relay driving circuit with anti-interference ability provided by the utility model includes: two resistors R1-R2, diode D1, two triodes Q1, Q2 and relay U1; wherein:

Point A and point F are two control points of the external control components, and point A is connected to the base of the first triode Q1 through the first resistor R1; the emitter of the first triode Q1 is connected to the +5V power supply connection; the collector of the first triode Q1 is connected with the cathode of the diode D1 and the port 1 of the control coil of the relay U1; the anode of the diode D1 is connected with the port 2 of the control coil of the relay U1 and the set of the second triode Q2 The electrodes are connected; point F is connected to the base of the second transistor Q2 through the second resistor R2; the emitter of the second transistor Q2 is connected to the reference ground plane 0.

The first resistor R1 and the second resistor R2 are both 5.1k ohm resistors; the first transistor Q1 is a PNP transistor, and its specific model is 8550, and the second transistor Q2 is an NPN transistor. The specific model is 8050; the diode D1 is a switching diode, and its specific model is D1N4148; the control voltage of the control coil of the relay U1 is +5V.

The relay drive circuit with anti-interference ability provided by the utility model has two control ports, and the circuit can be driven only when certain conditions are met. Compared with other methods, this circuit does not occupy a large amount of microcontroller resources in the external controller, which can improve the reliability of the system.

The relay drive circuit provided by the utility model has the following technical effects:

1. The utility model uses fewer devices and has higher anti-interference ability, which improves the reliability of the whole system.

2. The peripheral devices of the utility model are composed of resistors, diodes and triodes, which are relatively low in complexity and improve the processability of the product.

3. The driving circuit of the utility model can effectively suppress the short-term reverse overvoltage at the moment when the relay is turned off.

Description of drawings

Fig. 1 is a schematic diagram of a relay driving circuit with anti-interference ability provided by the utility model.

Detailed ways

The relay driving circuit with anti-interference ability provided by the utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the relay drive circuit with anti-interference ability provided by the utility model includes: two resistors R1-R2, diode D1, two triodes Q1, Q2 and relay U1; wherein:

Point A and point F are two control points of the external control components, and point A is connected to the base of the first triode Q1 through the first resistor R1; the emitter of the first triode Q1 is connected to the +5V power supply connection; the collector of the first triode Q1 is connected with the cathode of the diode D1 and the port 1 of the control coil of the relay U1; the anode of the diode D1 is connected with the port 2 of the control coil of the relay U1 and the set of the second triode Q2 The electrodes are connected; point F is connected to the base of the second transistor Q2 through the second resistor R2; the emitter of the second transistor Q2 is connected to the reference ground plane 0.

The first resistor R1 and the second resistor R2 are both 5.1k ohm resistors; the first transistor Q1 is a PNP transistor, and its specific model is 8550, and the second transistor Q2 is an NPN transistor. The specific model is 8050; the diode D1 is a switching diode, and its specific model is D1N4148; the control voltage of the control coil of the relay U1 is +5V; the driving voltage of the drive pin of the MCU involved in the utility model is +5V.

The working principle of the relay driving circuit provided by the utility model is as follows:

Point A and point F are two control points of external control components. When the MCU drives point A and point F to low level, since point A is low level, the collection of the first transistor Q1 of PNP nature The electrode and the emitter are turned on, and the first triode Q1 is in a saturation region. Since point F is at low level, the collector and emitter of the second NPN transistor Q2 are cut off, and the second transistor Q2 works in the cutoff region. As a result, the current cannot flow from point C to point H, causing the control coil of relay U1 to fail to work.

When the external control unit drives point A and point F to be high level, since point A is high level, the collector and emitter of the first transistor Q1 of PNP nature are cut off, and the first transistor Q1 works in the cut-off zone. Since point F is at a high level, the collector and emitter of the second transistor Q2 of NPN nature are turned on, and the first transistor Q1 works in the saturation region, so the current cannot flow from point C to point H, causing the relay The control coil of U1 does not work.

To sum up, only when point A is at low level and point F is at high level, can the first triode Q1 and the second triode Q2 be in the conduction state at the same time and work in the saturation region. At this time, the current can flow from point C to point H through the control coil of relay U1, and the relay U1 can work normally.

When the external control components are in the environment of strong electromagnetic interference, it is possible to drive the control point pins A and F to jump. From the above situation, it can be known that only when A is at low level and F is at When the level is high, the relay can be driven. Compared with other relay driving methods, the probability of this interference is obviously much lower.

The relay drive circuit with anti-interference ability provided by the utility model is different from the previous single-end drive relay scheme. This hardware solution can use fewer electronic devices to improve the product's strong anti-interference performance and realize Optimization of design.

Claims (2)

1. there is a relay drive circuit for antijamming capability, it is characterized in that: the described relay drive circuit with antijamming capability comprises: two resistor R1-R2, diode D1, two triodes Q1, Q2 and relay U1; Wherein:

A point and F point are two control points of external control component, and A point is connected with the base stage of the first triode Q1 by the first resistor R1; The emitter of the first triode Q1 is connected with+5V power supply; The collector electrode of the first triode Q1 is connected with the port one of the control coil of the negative electrode of diode D1, relay U1; The anode of diode D1 is connected with the collector electrode of port 2, the second triode Q2 of the control coil of relay U1; F point is connected with the base stage of the second triode Q2 by the second resistor R2; The emitter of the second triode Q2 is connected with reference horizontal plane of manufacturing 0.

2. the relay drive circuit with antijamming capability according to claim 1, is characterized in that: the first described resistor R1, the second resistor R2 are 5.1k ohmic resistor; First triode Q1 is PNP type triode, and its concrete model is the 8550, second triode Q2 is NPN type triode, and its concrete model is 8050; Diode D1 is switching diode, and its concrete model is D1N4148; The control voltage of the control coil of relay U1 is+5V.